The invention relates to a roofing composition comprising a blend of a thermoplastic elastomer and a vulcanizable elastomer. More particularly, the invention relates to a roofing composition comprising a blend of a thermoplastic elastomer containing at least two polymer blocks one of which is a crystalline polymer block and the other of which is an amorphous polymer block and a vulcanizable elastomer selected from the group consisting of EPDM, butyl, neutralized sulfonated EPDM, neutralized sulfonated butyl and mixtures thereof.
Elastomeric roofing compositions comprising blends of EPDM and butyl elastomers are known in the art as illustrated by U.S. Pat. Nos. 4,461,875 and 4,514,442. These patents relate to roofing compositions for use as roof sheeting or roof flashing which comprise 100 parts of an elastomer selected from the group consisting of EPDM, butyl rubber and an EPDM-butyl rubber mixture; 0.1 to 3.0 parts of a compound having the structural formula [(CH.sub.2).sub.n NCS].sub.2 S.sub.6, where n is 4 or 5; and 0 to 0.5 parts of a sulfur donor curative.
Compositions for other end use applications which contain blends of elastomers or elastomeric polymers including blends of thermoplastic elastomers and vulcanizable or vulcanized elastomers are known in the polymer arts as illustrated by the following patents:
U.S. Pat. No. 4,442,253 to Lundberg et al. relates to blend compounds of an amine neutralized sulfonated elastomeric polymer and an unsulfonated elastomeric or thermoplastic polymer. As disclosed in this patent, the amine terminated neutralized sulfonated elastomeric polymer is prepared by reacting an amine terminated polylactone with a sulfonated polymer derived from EPDM, butyl, partially hydrogenated polyisoprenes, partially hydrogenated polybutadienes, neoprene, styrene-butadiene copolymers or isoprene-styrene copolymers. Unsulfonated elastomeric or thermoplastic polymers which may be utilized in the blend include butyl rubber, polyvinyl chloride, polyisobutylene, and polyester-based polyurethanes. The blend compositions may be utilized as adhesive agents, thermoplastic elastomers and compatabilizers for other polymers.
U.S. Pat. No. 4,313,867 to Duvdevani relates to injection moldable type elastomeric compositions comprising blends of a neutralized sulfonated EPDM terpolymer, a styrene-ethylene/butylene-styrene block copolymer, a non-polar process oil and optionally a polypropylene thermoplastic resin. The patent indicates that the compositions may be utilized to produce high performance elastomeric articles such as footwear.
U.S. Pat. No. 4,248,758 to Wright relates to a blend of a crosslinked EPDM polymer and a thermoplastic elastomer comprising a linear or branched teleblock copolymer having the formula A--B--A or (A--B).sub.n --y, wherein A represents a block of polymerized monovinyl--substituted aromatic compound units, B represents a block of polymerized conjugated diene units, y is a residual unit from a polyfunctional coupling agent or a polyfunctional initiating species and n has a value from 2 to 6. The patent indicates that the blend compositions have high green strength and ozone resistance and can be utilized in applications as molded articles such as shoe soles, toys, containers and pipes and can also be employed in tires, gaskets, pressure sensitive adhesives and sealing and caulking compositions.
U.S. Pat. No. 4,177,184 to Condon relates to polymeric blends having utility for use as automotive exterior parts which comprise a selectively hydrogenated monoalkenyl arene/diene multiblock copolymer, a polyolefin, a filler, a fatty acid amide and a synthetic rubberizing polymer. As defined in the patent, the multiblock copolymer has at least two polymer end blocks A and at least one polymer midblock B. Both blocks A and B may be either homopolymer, random or tapered copolymer blocks as long as the A blocks individually predominate in monoalkenyl arenes and the B blocks individually predominate in dienes. Synthetic rubberizing polymers disclosed in the patent include non-hydrogenated monoalkenyl arene-conjugated diene multiblock copolymers, selectively hydrogenated monoalkenyl arene-cojugated diene A--B two block copolymers wherein A and B are as defined above, ethylene-propylene copolymers, EPDM terpolymers, polyisobutylene, butyl rubber, polybutadiene and neoprene.
U.S. Pat. No. 4,102,849 to Bouton et al. relates to an oil-extended hydrogenated diblock copolymer composition comprising 10-200 parts of oil per 100 parts of hydrogenated diblock copolymer comprising one block of hydrogenated polybutadiene and one block of a hydrogenated random copolymer of a vinyl arene such as styrene and butadiene. The patent at column 6 lines 63-68, discloses that the hydrogenated diblock copolymer may be modified by the presence of asphalt, wax, polyvinyl compounds such as polystyrene, polymers of alpha-olefins such as polypropylene or polyethylene or it may be mixed with either natural or synthetic rubbers such as polyisoprene and polybutadiene. The patent indicates that the oil-extended hydrogenated diblock copolymers may be utilized in producing rubber hose, shoe soles, tires, industrial and automotive goods, etc.
U.S. Pat. No. 3,526,606 to Minekawa et al. relates to rubber compositions comprising a block copolymer, a rubber, a process oil and a filler. Block copolymers disclosed in the patent are styrene/butadiene block copolymers containing 60 to 95% by weight of styrene having the structure B.sub.1 --A--B.sub.2, where B.sub.1 and B.sub.2 represent a polybutadiene or a 1,3-butadiene/styrene random copolymer block having a styrene content of less than 50% by weight, A represents a polystyrene block with the composition ratio of B.sub.1 and B.sub.2 blocks being respectively 5-90% by weight based on total weight of block copolymer and the composition ratio of the A block being respectively 5-75% by weight bssed on total weight of block copolymer. Rubbers which are disclosed in the patent include emulsion-polymerized butadiene/styrene copolymeric rubber, emulsion or solution polymerized polybutadiene rubber, solution-polymerized butadiene/styrene copolymeric rubber of low styrene content, polyisoprene rubber, emulsion polymerized butadiene/acrylonitrile copolymeric rubber, polychloroprene rubber or ethylene/propylene copolymeric rubber. The patent indicates that the rubber compositions may be utilized in shoe soles, hard vulcanized products and hard foamed products.
Thermoplastic elastomers containing a crystalline polymer block and an amorphous polymer block are also known in the art as illustrated by U.S. Pat. Nos. 3,634,549, 4,102,849 and 4,491,652.
U.S. Pat. No. 3,634,549 to Shaw et al relates to hydrogenated block copolymers in which the block copolymers prior to hydrogenation have the general formulae: EQU (A--B).sub.1-5 (B--A).sub.1-5
and EQU A--(B--A).sub.1-5
wherein each A is a polybutadiene block having an average molecular weight between about 5,000 and about 100,000 and each B is an elastomeric diene-monovinyl arene random copolymer block having an average molecular weight between about 25,000 and about 250,000 and a weight percent condensed monovinyl arene between about 5 and about 50, and wherein at least about 80% of the butadiene and any other diene double bonds are reduced by hydrogenation.
U.S. Pat. No. 4,102,849 to Bouton et al. described above discloses a hydrogenated diblock copolymer comprising one block of hydrogenated polybutadiene and one block of a hydrogenated random copolymer of a vinyl arene and butadiene. The hydrogenated diblock copolymer is a thermoplastic elastomer containing a crystalline polymer block formed by hydrogenation of polybutadiene and an amorphous polymer block formed by hydrogenation of the random vinyl arene-butadiene copolymer block.
U.S. Pat. No. 4,491,652 to Matthews et al. relates to a thermoplastic elastomer which is a sequentially prepared propylene and (ethylene-propylene) polymer or a sequentially prepared propylene, (ethylene-propylene) and propylene polymer. One of the thermoplastic elastomers disclosed is a thermoplastic elastomeric sequentially prepared polymer having (A) crystalline polypropylene segments of isotactic polypropylene and (B) amorphous segments of elastomeric ethylene-propylene, said segments (A) and (B) being partially block copolymerized to each other, the weight ratio of (A) to (B) segments being within the range from 10:90 to 75:25.